Ostracod FireworksWhen an ostracod is swallowed, it emits a burst of light, making the cardinal fish spit it out.
"They've been called fish fireworks, and their glowing displays are like nighttime light shows on the water. Ostracods are a very old species of crustacean with a trait called bioluminescence. That's a fancy way of saying they light up, like fireflies. But unlike fireflies, ostracods have extracellular bioluminescence. They shoot light out of their bodies and into the water. The behavior is part mating ritual, part defense mechanism.
There are ostracods in every world ocean that are luminescent, but only in the Carribbean do you find these ones that have these complex patterns, and it's probably related to the closing of the Panama Isthmus about 3 million years ago. It could startle their predators visually, or it could actually bring in the predator of their attacker, which is called the burglar alarm effect.
In this gif the tiny ostracod is almost eaten by the much larger fish, but the cardinal fish spits the ostracod out once the ostracod begins to emit light. Exactly why this causes the cardinal fish to spit the ostracods isn't known, but there are theories."
✪ Watch the BBC short clip here: http://www.bbc.co.uk/nature/28838200
✪ And some info about Crustaceans:https://en.wikipedia.org/wiki/Crustacean
✪✪✪ HT: +Magnus Fahlén